Gen IV LS3 build elements
 

So if a guy wanted to build a Gen IV LS3 starting with a late model Camaro salvage motor with a goal of high reliability 500-525 crank hp range or more if realistically obtainable. What modifications and critical components need to happen?

Motor could be subject to occasional or daily driving in town, a few 500-1000 mile road trips, and handle a few 'recreational' track days during the year.

Bottom end

Valve train

Oiling

Tunable EFI

Cooling/venting

Clutch

Machining tips/tricks

I ask because a friend just had a longtime local performance motor shop dropped in his lap. This shop had never done LS motors. Old school GM, Ford, Mopar V8's for drag racing, boats, sprint cars, and performance street cars was the focus.

The new owner knows they need to embrace the LS platform to survive and wants to get a Gen IV to analyze and experiment with.

I want to get him pointed in the right direction with solid fundamentals and advice from those with experience.

Thanks :thumbsup:

HP Tuners software for the stock PCM or the Holley hp/Dominator setups are probably the best place to start. There's some decent time learning right there--I might get to it myself in a few years, as I just stuck a Gen IV LS in my Falcon. Tons of power seems to come just from cam swaps and tuning in these motors, so there's a lot of homework to do right there.

I'll be keeping the VVT and cylinder deactivation stuff on mine (along with the DBW throttle), because I'm all about efficiency . . .

I'll look forward to any info dumps that happen here.:goggles:

Scared me for a minute there Sieg...

Yes there is. :thumbsup:

The offer was made to use Norwood as the recipient.......but I haven't seen an engine cover that looks better to me than my Gen 1 SBC motor and everyone knows I don't have the talent to handle any more horsepower.

I did find him a really nice C10 shortwide today that would be a good donor/shop truck. :unibrow:

All an LS3 needs to make that kind of crank HP is a cam (and a mild cam at that). I had an LS3 in my previous car (71 Camaro), completely stock internally other than a 227/235 113 LSA Comp LSr cam. Headers too, of course. It made ~465 HP and 430 TQ at the rear wheels. It survived about 20 track days without a hiccup. It idled and drove almost like a stock late model Vette.

So 550 - 575 at the crank is a reasonably safe target?

What are the LS3's common stress related failures?

I would use the LS3 525 cam and springs, GM did tons of testing on that combo, it makes good power and is easy on the valvetrain. The question is... how good does the car handle that it's going in? The higher the grip level is the more time you need to spend on helping it keep oil where it belongs. A oilpan with good baffling (I'm a fan of the Autokraft pan), accusump, oil cooler, and good venting on the valve covers and valley through a catch can.

Thanks Tim. Completely agree with the handling statement and will add brakes to that. With the new generation crate powerplants it's an uncomforting thought wondering what type of chassis' they may be going in.....and the fact that they could be coming at you on public roads in a manner similar to a Skud missile.

One the the better tracks near us (6 hours) is Thunderhill and T2 is an oil starver for sure. It's a pure 180*3rd gear radius that's probably damaged more than it's share of motors.

The GMPP LS3 525 motor is what I've been looking at as a decent target for the shop to improve on by addressing the oiling and venting issues along with insuring the motor gets adequate fuel, that should deliver a reliable cost effective package in my amature mind at least.

At what point does the Nodular Iron crankshaft/rods/pistons become a weak link in an LS?

The bottom end parts in an LS3 are far more robust than in the production Gen 1 small blocks. I simply wouldn't worry about the bottom end at any normally aspirated power level. The failures I've seen on LS motors at the track almost all seem to be related to either oiling issues or valvetrain.

You do want to make sure you're using an ECU with correctly calibrated knock sensors (like the GM ECU, or a correctly calibrated Holley or AEM). LS3s are quite knock sensitive, especially on the crap gas we get here in Oregon. I dyno tuned a 2011 Camaro SS yesterday with stock cam, headers, cold air, and I couldn't get it to keep more than 19 degrees timing at WOT. And it still made 413 hp at the rear wheels!

Also if you're going to track it, overdo the cooling system as much as possible, especially in a 1st gen f-body, which has smaller core size than the 2nd gens. Ron Davis or C&R radiator, secondary oil cooler, tightly seal the high pressure area at the cowl. Also a 160 thermostat if you don't care much about the heater :)